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PROPERTY, PLANT AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2025 | Mar. 28, 2025 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Property, Plant and Equipment [Line Items] |  |  |  |  |
Depreciation expense |  |  | $ 82,609 | $ 65,507 | $ 57,720
Asset impairment charges | $ 27,829 | $ 31,766 | 59,596 | $ 0 |
Accumulated depreciation, eliminated amount |  |  | 14,965 |  |
Buildings and related improvements |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Asset impairment charges |  |  | 2,918 |  |
Construction in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Asset impairment charges |  |  | 32,463 |  |
Leasehold improvements |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Asset impairment charges |  |  | 1,548 |  |
Machinery and equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Asset impairment charges |  |  | $ 22,667 |  |

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